This invention relates to packaging machinery of the type in which a paperboard carton is first formed from a flat paperboard blank by a plunger reciprocating through a forming die, the formed carton with open top being stripped from the retracting plunger and deposited on to a conveyor system at another position along which a product is delivered into the carton, which then receives a separate lid at a further position or has integral flaps folded down and secured.
With the usual cyclical mechanical drive for the plunger in the prior art carton formers, the timing for the blank feeder, and the conveyor system and product delivery, is all set from the timing of the plunger. Also, the motion of the plunger is rigidly determined by the drive means. Even if the length of stroke of the plunger can be adjusted, it is unlikely to vary its speed curve, which is usually sinusoidal with a maximum speed at or near to its passage through the forming die. This prior art packaging machinery is illustrated, for example, in applicant's U.S. Pat. No. 3,260,174 issued Jul. 12, 1966. Except for refinements in a few of the mechanical drive components, there have been no significant changes in this basic drive and control system in the last 25 years.